Many systems, such as battery charging systems, require both over voltage and over current protection in order to prevent damage to electronic components included within a system such as a battery charging system. To date, protections from input over voltage, battery over voltage and charge current over current have required the use of three separate circuits and/or chips in order to protect a system from these over voltage and over current conditions. This is especially so with respect to Li-ion batteries. A Li-ion rechargeable battery is very sensitive to over charge. Over charging a Li-ion battery may lead to explosion, flame or other hazardous situations. A charging system needs to charge the battery to a high precision final voltage so that the battery is not over charged, neither under charged. From safety point of view, it is very critical that the Li-ion battery is properly protected against over charge. Over charge is typically a result of failures in a charging system. A charging system typically consists of an ac/dc converter (typically named a wall adapter or an ac adapter) and a charging circuit that provides precision current limit and precision final battery voltage. An over-charge protection function is typically residing in a Li-ion battery pack to protect the battery against charging system failures. However, some unqualified after-market battery packs do not have the protection function built-in, which greatly increases the risk of explosion, flame, or other hazardous situations when a single failure occurs in the charging system. When any of the above events occurs, the manufacture of the handheld device will be liable to any resulted damage.
The use of multiple chips for providing these protections requires a great deal of space within an electronic device, including three separate chips for providing the protections. Thus, there is a need for a chip for providing an electronic device with multiple types of over voltage and over current protection in order to save space within the electronic device requiring such over voltage and over current protection.